Line television



July 5, 1938. Y A. Mc| NICOLSQN. 2,122,750

LINE TELEVISION Filed July 5, 1954 2 Sheets-Sheet l TRANS.

INVENTOR ALEXANDER McLEAN NICOLSON ATTORNEY y 1938. A. MCL. NICOLSCSN 2,122,750

LINE TELEVISION Filed July 5, 1934 2 Sheets-Sheet 2 CIRCUIT FIG. 7

m INVENTOR 6ft ALEXANDER MCLEAN NICOLSDN BYW%MW ATTORNEY Patented July 5, 1938 PATENT orrics LINE TELEVISION Alexander McLean Nicolson, New York, N. Y., assignor to Communication Patents, Inc., New York, N. Y., a corporation of Delaware Application July 5, 1934, Serial No. 733,705

'1 Claims.

invention relates to television systems and particularly 7 to certain fundamental elements thereof. I An object of the invention is to transmit pictures of objects or their images at a rate to produce the illusion of motion. I Another object of the invention is to transmit and receive pictures of objects or their images a without mechanically moving elements.

A further object of the invention is to reduce the linear motion of an ionized or light beam into a solid surface or two-dimensional field.

A still further object of the invention is to transmit pictures of objects or their images in two directions over common apparatus.

- In several of my television systems such as those-disclosed in Patent No. 1,863,278, issued I T June 14, 1932 and Patent No. 1,839,696, issued January 5, 1932, I utilize an electrical discharge or are movable by the force of a magnetic field in which it is disposed. The present invention utilizes a simplifiedmodification of such an electro -dynamic are system, as well as an ionized cathode ray beam, such as disclosed in my Patent No. 1,470,696, issued'October 16, 1923.

' low. pattern into a solid field is by means of a stationary mechanical structure having fixed terminating paths, one group of terminals being in the form of a circle or ellipse or other geometrical pattern and the others in the form of a :surface. That is, small tubes transmitting in a solid surface are distributed at the. other terminals in the form of a continuous ring of 1 single units. .As the scanning medium is propagated along the terminals arranged in the continuous path, light is propagated through the tubes to the terminals arranged in the solid pattern. ,The terminals forming the surface may be distributed in any manner'desired or may have various shapes, inasmuch as the scanning rate is sufficient to. maintain the appearance of a lighted field at all times. With the possibility Of such avaried distribution, the waterfall effect, such as is now obtained with scanning systems which scan from top to bottom, is eliminated. Also by the use of two concentric circular rows, the other terminals forming a solid field, two-way transmission and reception is easily accomplished.

The invention itself, however, both as to its method of operation and its fundamental principles, together with additional objects and advantages thereof, will best be understood from the following description-of certain specific embodiments, when read in conjunction with the accompanying drawings in which:

Fig. 1 shows a transmitter using an electrical discharge scanning system;

Fig. 2 shows a receiving system for the transmitter of Fig. 1;

.Figs. 3, 4, 5 and 6, inclusive, show various modifications of the translator;

Fig. 7 shows a two-Way communicator utilizing a cathode ray tube;

Fig. 8 shows another embodiment of the twoway television system using an electrical discharge scanning system, and

Fig. 9 is a detail View of an element of Fig. 8.

Referring now to Fig. l, a simple arc rail system 5 comprises electrode rails 6 and a field winding shown as a single turn I, thefi'eld winding being supplied with energy from a source 8 under control of a rheostat 9. The are rails 6 are supplied with energy from a direct current source [2 under control of a rheostat I3. In the same circuit with source l2 and rheostat I3 is the secondary of a transformer I4.

This are system is a simple form of the are used in my above-mentioned patents and is one in which the speed and intensity of the are are easily controlled. The light produced by the are as it is propagated along the rails 6 is focused by lens 16 on the terminals of the light tubes of translator l8, the tubes being formed in a circle at l9, and in a solid field surface at 20. Light from the are arriving at the terminals 20 is projected upon an objectO through a lens2| in the usual manner. Reflected light from the object O is detected by a photo-electric cell or similar photo-sensitive device 25, which transforms the varied light intensities into electrical currents. These currents are amplified inamplifier 26, the output thereof being impressed upon a transmitter 21 for transmission over an antenna 28 or wire lines. A portion of the energy from the photo-electric cell is fed back to the arc rails 6 through the transformer I4 for purposes of synchronism, this method of synchronism being the subject-matter of a patent application filed by Henderson C. Gillespie, Serial No. 584,7 97, filed January 5, 1932.

The unit I8 may be constructed in several ways, such as by the use of a plurality of fine quartz or hollow internal reflecting tubes which may be uniform or tapered so that the circular terminal path I3 is smaller than it would be if the tubes were uniform. These tubes may be arranged by units or grouped together and then separated by a conical wedge, after which they are held together by a hardening material like wax or bound mechanically. The entire unit may also be molded by using solid wires inserted in a form, the wires being arranged at one end in a continuous ring of unit width and grouped at the other end in any desired form such as'a circle or square. These wires may have a slight insulating material thereon such as cloth, paper or grease, which will burn or be destroyed when the casting material is poured. After the casting has hardened, these wires are removed and the holes blown with a fine reflecting dust or liquid. It is also to be understood that one set of terminals may form a concave, convex or plane surface or that the individual terminals may have similar formations.

The tubes or holes may be circular or have various shapes, such as triangular as shown in Fig. 6, square or rectangular as shown in Fig. 5, or vary at each terminal, such as triangular at one end and square at the other. Furthermore, they may be arranged so that the tubes forming a solid field at one end form a plurality of circles at the other end, such as shown in Figs. 3 and 4. This modification reduces the diameter of the circles in comparison with the size of the screen. All the circles may be used for incoming signals or each circle have a separate function as for two-way television shown hereinafter.

It is believed the operation of the electrodynamic scanning system of Fig. 1 is obvious to those skilled in the art, but will be briefly reviewed. An electrical discharge is initiated and maintained between electrodes 6 by the voltage from source l2, and, under the influence of the magnetic field is propagated along the electrodes at a speed dependent upon the separation of the electrode rails, the strength of the field and the current in the discharge.' Rheostats 9 and I3 are adjusted to provide the speed desired. As the light from the arc is propagated on the terminals IQ of the tubes l8 and projected therefrom at the terminals 20, the object O is scanned in unit areas as the arc is propagated along the rails 6. The return of some of the photo-cell currents to the arc varies the speed thereof in accordance with the speed of the receiving arc, which is varied as the incoming signals are impressed thereon. There is a slight gain in sensitiveness due to this regeneration, but it is not cumulative as has been demonstrated in experiments, but produces an excellent control for the transmitting and receiving arcs.

Referring now to Fig. 2 showing the receiving system for the above transmitter, an antenna 30 impresses its energy upon a receiver 3|, the output of which is amplified inamplifier 32. An are system 34, similar to the are system 5 of Fig. 1, comprises electrode rails 35 and field winding 36 supplied from an energy source 3'! under control of a rheostat 38. The same type of tube system as I8 is shown at 40 comprising a surface arrangement of the terminals at 4| and a circular line arrangement to the terminals at the other end 35. terminals are adjacent the electrodes 35, this being a variation of the arrangement shown in Fig. 1, the two, however, being substitutes for one another. That is, as the arc is created between the rails 35 from an energy source 43 under control of a rheostat 44, the arc is propagated along the rails by the field 36 passing the immediately adjacent terminals of the tubes 40. The light from the arc could just as well be projected through a lens similar to the lens H5 in Fig. 1, or the lens I6 could be illuminated in Fig. 1 and the terminals l9 placed adjacent the arc path. One system is shown in Fig. 1 and the other in Fig. 2 for the purpose of showing the two possible arrangements.

The operation of the receiver is simple in that the incoming signals impressed across the arc rails 35 vary the intensity thereof, these varying intensities being transmitted to the field terminals 4| where they produce a light image of the object O. The are may vary somewhat in speed as the intensity varies, but this variation is also followed at the transmitter so they remain in synchronism.

Referring now to the two-way television system disclosed in Fig. 7, a similar tube arrangement 48 has its field terminals arranged in the form of a square of two sections 59 and 5| and its other. terminals arranged in the .form of two circles .52 and 53. As shown in the drawings, circle 53 is for reception and has its tube terminals in section 5| and circle 52 .for transmission'with its tube terminals in section 50. It is obvious that the sections 50 and 5| could be arranged horizontally or could be separated somewhat without departing from the spirit of the invention. A lens 54 placed between the section 50 and an object projects the image of the object on section 50, the light being carried through the unit area divisions to the transmitting ring 52, which has transparent capped terminals coated with a photo-sensitive material. The lens 54 does not inter,- fere with the objects observation of receiving section The other ring, namely 53, has the tubes capped and covered with the photo-lumie nous material which will fluoresce upon bombardment by the electrons in a cathode ray stream. It is to be understood that the tubes may all be of the same size or vary in size aswell as be distributed in serial order according to the type and quality of picture to be transmitted. 7

Sealed to the outer edge of the circularly arranged terminals'52 is a cathode ray tube envelope 58 having therein two cathodes 59 and 60 supplied from an energy source 6| under control of a rheostat 62; two defining diaphragms 55 and 56, two control or concentrating electrodes 64 and 65 polarized by energy sources 66 and 61, respectively, and two sets of deflecting plates 69 connected to a sweep circuit well known in the art. Thus the tube may be of the usual type with the usual arrangement of electrodes, except that there'are two rotating cathode ray beams from two cathodes under separate intensity controls. Positioned near the photo-sensitive material on ring 52 is an electrode H which is connected to the cathode 60 through the primary of a transformer 12 and a high potential source 13. The current flowing in the primary of the transformer 12 will vary in accordance with the electrons emitted by the photo-sensitive material on the ring 52, which is varied according to the light reaching it through the tubes. This current variation may be transmitted to an amplifier '14 and a; transmitter for transmission over antenna 16 In this case the circularly arranged or for impression on 'wire lines. For synchronizing, a portion of the current from the sweep transmitter I for purposes of maintaining the sweep circuit at the other receiver in step. The

receiving portion of thecircuit includes an antenna 80, receiver 8!, amplifier 82 and an output transformer 83 for impressing the incoming signals on the control electrode 64. The sweep circuit frequency is filtered out by a filter 85 and impressed upon the sweep circuit oscillator for purposes of synchronism, as mentioned above.

The operation of this two-way television system isas follows. The image of the object O is carried through the tubes in unit areas arranged in 4 circle 52 and scanned by a cathode ray of consystem thus provides a simple system of two-way shown utilizing electro-dynamic arcs, but in which the observation screen is common with the scanning screen. A tube translator 8'! has two circularly arranged terminals 88 and 89, 88 being for transmission and terminating in small terminal 90, and terminals 89 being for reception and terminating in large terminals 9|. As shown in Fig. 9, each of the small tubes are capped with beam projecting lenses 93 for projecting scanning light over the object 0, these beams being somewhat larger at the object to completely cover it. With this arrangement no large intervening lens is required and the screen is perfectly observable by the object being scanned.

An are system 93 is disclosed in this embodiment having scanning electrodes 94 and receiving electrodes 95, both of which are positioned in a magnetic field formed by a field winding illustrated, as the single turn 96, supplied from a source 91 under control of rheostat 98. The light beams from both' arcs are projected through a lens 99 on the rings 88 and 89 for transmission and reception, respectively. As shown in Fig. 1, light of constant intensity projected from the are 94 traverses the tubes having their terminals in ring 88 and at 99 and is projected on to the object 0 through lenses 93, which may be of quartz. The photo-electric cell 192 detects the varying light and shade densities of the object and, its output is impressed on an amplifier Hi3 and then on the transmitter N14 for transmission from an antenna I95. A portion of the photoelectric cell output is transmitted through a transformer I06 to electrodes 94, the electrodes 94 being polarized by a source I01 under control of a rheostat I08. This feed-back is for synchronism explained above in connection with Fig. 1. To prevent the light of the received image from affecting the photo-sensitive device I02, this cell could be made sensitive to only the transmission scanning light by construction or by an intervening filter.

The receiving portion of this system includes an antenna H0, receiver Ill, amplifier H2, and

are polarizing source H3 and rheostat H4. This portion of the apparatus operates in the same manner as that disclosed in Fig. 2. 1

In the operation of this system, the observer 0 views the incoming image on terminals 9!, whilehe is being scanned with light projected from the terminals 90. The scanning lenses 93, therefore, do not interfere with his observation of the incoming image. It is quite obvious that the are system 93 could be placed adjacent the rings 83 and 89 in the same manner as shown in Fig. 2, thus eliminating the lens 99. It is to be understoodthat each arc may provide light beams of different wave lengths such as partially invisible light of the infra-red or ultra violet frequencies for transmission and visible light in the intermediate spectrum for reception, thus avoiding glare and increasing efliciency. The disclosure of-such arcs is found in my co-pending application, Serial No. 275,672, filed May 7, 1928. With the transmitting and receiving light beams of different frequencies, the same tube could carry both beams without interference, thus providing finer detail for the system.

For the sake of clearness only a limited number of channels have been illustrated but it is to be understood that the number may be increased in accordance with the size of the image or fineness of detail desired. With the two-Way television system disclosed in Figs. 7 and 8 just described, the object 0 could write messages while being scanned, the messages being carried to the receiving terminals for observation, thus completing two-way communication by both picture and words.

What is claimed is:

1. In a two-way television system, means for producing a plurality of radiating beams of unit area dimensions, one of said beams being of constant intensity, means for varying another of said beams in accordance with the light and shade densities of an object, means for producing light with at least one of said beams, a group of light channels having one set of terminals arranged in a stationary circular row, means for projecting said light on said stationary circular row of light terminals in serial order, said light channels having the other terminals thereof arranged in two dimensions, means for projecting light from said two-dimensional terminals, another group of light lizing said constant intensity beam as a commutator device for obtaining current variations proportional to the light intensities in one group of said channels.

2. In a two-way television system, means for producing a plurality of light beams moving in lines, a plurality of light channels having one set of terminals arranged in a corresponding plurality of lines to receive light from said beams, the other terminals of said channels being arranged in a two-dimensional pattern forming a surface, the terminals of one of said lines being intermingled with the terminals of the other of said lines, and means for projecting light in beams from one set of said terminals, the other set of said terminals projecting diffused light therefrom.

3. In a two-way television system, an electrodynamic are system having two sets of electrodes and a magnetic field for driving a plurality of arcs along said electrodes, a translator formed of a plurality of independent light channels, one set of terminals of which form a surface and the other terminals form two concentric rows of unit area width, and means for respectively associating the light from said arcs with, said rows,

of terminals, the light from one of said arcs being used for transmission and the light from the other of said arcs being used for reception.

4. A two-way television system in accordance with claim 3 in which said transmitting arc has a larger proportion of invisible light than said receiving arc.

5. A scanning screen for a tWo-waytelevision system wherein a single screen is used for both scanning an object and for reproducing an incoming image simultaneously, means for producing a plurality of light beams, means for modulating one of said beams, a translator formed of a plurality of independent light transmitting channels having one set 'of terminals arranged as a surface and the other set of terminals arranged in two concentric hollow rows of single-channel width, substantially one-half of said channels being in each of said rows, and means for projecting said modulated light on one of said rows and constant intensity light on the other of said rows of terminals, the terminals of said channels receiving said modulated light and the terminals of said channels receiving constant intensity light being intermingled with each other within said surface.

6. A scanning screen in accordance with claim 5 in which the surface terminals of said channels transmitting constant intensity light have beam projecting lenses thereon.

7. A scanning screen in accordance with claim 5 in which the surface terminals of said channels transmitting constant intensity light have beam projecting lenses thereon and the surface terminals of said channels transmitting modulated light having light diffusing lenses thereon.

ALEXANDER MGLEAN NICOLSON. 

